[PATCH v2 08/11] cpufreq: amd-pstate: Merge amd_pstate_highest_perf_set() into amd_get_boost_ratio_numerator()

Mario Limonciello
2024-09-03T20:37:16Z

The special case in amd_pstate_highest_perf_set() is the value used
for calculating the boost numerator. Merge this into
amd_get_boost_ratio_numerator() and then use that to calculate boost
ratio.

This allows dropping more special casing of the highest perf value.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v1->v2:
* Document that preferred cores will have different values for highest
perf.
* Fix an uninitialized variable caused by merge
---
Documentation/admin-guide/pm/amd-pstate.rst | 3 +-
arch/x86/kernel/acpi/cppc.c | 16 +++++++
drivers/cpufreq/amd-pstate.c | 52 ++++-----------------
3 files changed, 28 insertions(+), 43 deletions(-)

diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index d0324d44f5482..e13915c540648 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -251,7 +251,8 @@ performance supported in `AMD CPPC Performance Capability <perf_cap_>`_).
In some ASICs, the highest CPPC performance is not the one in the ``_CPC``
table, so we need to expose it to sysfs. If boost is not active, but
still supported, this maximum frequency will be larger than the one in
-``cpuinfo``.
+``cpuinfo``. On systems that support preferred core, the driver will have
+different values for some cores than others.
This attribute is read-only.

``amd_pstate_lowest_nonlinear_freq``
diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
index df367bc359308..956984054bf30 100644
--- a/arch/x86/kernel/acpi/cppc.c
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -9,6 +9,7 @@
#include <asm/processor.h>
#include <asm/topology.h>

+#define CPPC_HIGHEST_PERF_PERFORMANCE 196
#define CPPC_HIGHEST_PERF_PREFCORE 166

enum amd_pref_core {
@@ -245,6 +246,21 @@ int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
*numerator = boost_numerator;
return 0;
}
+
+ /*
+ * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f,
+ * the highest performance level is set to 196.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=218759
+ */
+ if (cpu_feature_enabled(X86_FEATURE_ZEN4)) {
+ switch (boot_cpu_data.x86_model) {
+ case 0x70 ... 0x7f:
+ *numerator = CPPC_HIGHEST_PERF_PERFORMANCE;
+ return 0;
+ default:
+ break;
+ }
+ }
*numerator = CPPC_HIGHEST_PERF_PREFCORE;

return 0;
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index c29cdf2d3882c..3ae41af6f041e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -52,8 +52,6 @@
#define AMD_PSTATE_TRANSITION_LATENCY 20000
#define AMD_PSTATE_TRANSITION_DELAY 1000
#define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
-#define CPPC_HIGHEST_PERF_PERFORMANCE 196
-#define CPPC_HIGHEST_PERF_DEFAULT 166

#define AMD_CPPC_EPP_PERFORMANCE 0x00
#define AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80
@@ -372,43 +370,17 @@ static inline int amd_pstate_enable(bool enable)
return static_call(amd_pstate_enable)(enable);
}

-static u32 amd_pstate_highest_perf_set(struct amd_cpudata *cpudata)
-{
- struct cpuinfo_x86 *c = &cpu_data(0);
-
- /*
- * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f,
- * the highest performance level is set to 196.
- * https://bugzilla.kernel.org/show_bug.cgi?id=218759
- */
- if (c->x86 == 0x19 && (c->x86_model >= 0x70 && c->x86_model <= 0x7f))
- return CPPC_HIGHEST_PERF_PERFORMANCE;
-
- return CPPC_HIGHEST_PERF_DEFAULT;
-}
-
static int pstate_init_perf(struct amd_cpudata *cpudata)
{
u64 cap1;
- u32 highest_perf;

int ret = rdmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
&cap1);
if (ret)
return ret;

- /* For platforms that do not support the preferred core feature, the
- * highest_pef may be configured with 166 or 255, to avoid max frequency
- * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as
- * the default max perf.
- */
- if (cpudata->hw_prefcore)
- highest_perf = amd_pstate_highest_perf_set(cpudata);
- else
- highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
-
- WRITE_ONCE(cpudata->highest_perf, highest_perf);
- WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
+ WRITE_ONCE(cpudata->highest_perf, AMD_CPPC_HIGHEST_PERF(cap1));
+ WRITE_ONCE(cpudata->max_limit_perf, AMD_CPPC_HIGHEST_PERF(cap1));
WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
@@ -420,19 +392,13 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
static int cppc_init_perf(struct amd_cpudata *cpudata)
{
struct cppc_perf_caps cppc_perf;
- u32 highest_perf;

int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
if (ret)
return ret;

- if (cpudata->hw_prefcore)
- highest_perf = amd_pstate_highest_perf_set(cpudata);
- else
- highest_perf = cppc_perf.highest_perf;
-
- WRITE_ONCE(cpudata->highest_perf, highest_perf);
- WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
+ WRITE_ONCE(cpudata->highest_perf, cppc_perf.highest_perf);
+ WRITE_ONCE(cpudata->max_limit_perf, cppc_perf.highest_perf);
WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
WRITE_ONCE(cpudata->lowest_nonlinear_perf,
cppc_perf.lowest_nonlinear_perf);
@@ -905,8 +871,8 @@ static u32 amd_pstate_get_transition_latency(unsigned int cpu)
static int amd_pstate_init_freq(struct amd_cpudata *cpudata)
{
int ret;
- u32 min_freq;
- u32 highest_perf, max_freq;
+ u32 min_freq, max_freq;
+ u64 numerator;
u32 nominal_perf, nominal_freq;
u32 lowest_nonlinear_perf, lowest_nonlinear_freq;
u32 boost_ratio, lowest_nonlinear_ratio;
@@ -928,8 +894,10 @@ static int amd_pstate_init_freq(struct amd_cpudata *cpudata)

nominal_perf = READ_ONCE(cpudata->nominal_perf);

- highest_perf = READ_ONCE(cpudata->highest_perf);
- boost_ratio = div_u64(highest_perf << SCHED_CAPACITY_SHIFT, nominal_perf);
+ ret = amd_get_boost_ratio_numerator(cpudata->cpu, &numerator);
+ if (ret)
+ return ret;
+ boost_ratio = div_u64(numerator << SCHED_CAPACITY_SHIFT, nominal_perf);
max_freq = (nominal_freq * boost_ratio >> SCHED_CAPACITY_SHIFT) * 1000;

lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
--
2.43.0